Analysis of information sources in references of the Wikipedia article "شاهنشاهی ساسانی" in Persian language version.
In the Middle Persian period (Parthian and Sassanid Empires), Aramaic was the medium of everyday writing, and it provided scripts for writing Middle Persian, Parthian, Sogdian, and Khwarezmian.
The Armenian defeat in the Battle of Avarayr in 451 proved a pyrrhic victory for the Persians. Though the Armenians lost their commander, Vartan Mamikonian, and most of their soldiers, Persian losses were proportionately heavy, and Armenia was allowed to remain Christian.
So spirited was the Armenian defense, however, that the Persians suffered enormous losses as well. Their victory was pyrrhic and the king, faced with troubles elsewhere, was forced, at least for the time being, to allow the Armenians to worship as they chose.
